A system and method for improving beam pointing accuracy for space laser communication

Abstract

The application provides a system for improving the beam pointing accuracy of space laser communication, comprising a laser, an electro-optical modulator, an optical phased array, a beam splitter, an infrared camera, a signal source and a computer; the laser is connected with the electro-optical modulator and used for emitting laser; the electro-optical modulator is used for modulating the received laser; the signal source is used for driving the electro-optical modulator based on the control of the computer; the optical phased array performs coarse pointing of the beam angle based on the control of the computer; the beam splitter transmits part of the received laser as laser emission and transmits part of the received laser as feedback light to the infrared camera; the infrared camera is used for transmitting the collected feedback light image to the computer; the computer calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, controls the laser frequency of the laser and compensates the pointing error, thereby improving the beam pointing accuracy of long-distance space laser communication.

Description

Technical Field

[0001] This invention relates to the field of laser communication technology, and more specifically to a system and method for improving the beam pointing accuracy of space laser communication. Background Technology

[0002] Compared to traditional microwave communication, laser communication features high bandwidth, small beam divergence angle, and resistance to electromagnetic interference. Furthermore, laser communication offers advantages such as higher transmission rates and better communication security. Therefore, laser communication is widely used in the field of communications.

[0003] Specifically, space laser communication, with its high communication rate, long transmission distance, and resistance to electromagnetic interference, is widely used in inter-satellite communication and satellite-to-ground communication links. Long-distance laser communication links require extremely high beam pointing accuracy, on the order of μrad. Traditional servo tracking systems use a turntable combined with electromagnetic mirrors to achieve high-precision beam pointing over large angles, but this results in difficulties controlling system size, weight, and power consumption. Using an optical phased array antenna can greatly simplify system size and power consumption while achieving beam pointing over a wide angle range. However, due to current technological limitations, the number of elements in an optical phased array antenna is limited, and the pointing accuracy is typically on the order of hundreds of μrads, which is insufficient to meet the beam pointing requirements of space laser communication. Furthermore, the open-loop pointing of an optical phased array antenna also makes it difficult to guarantee the system's accuracy under the influence of environmental factors.

[0004] The above-mentioned problems urgently need to be solved. Summary of the Invention

[0005] This invention aims to overcome at least one of the aforementioned drawbacks of the prior art. On one hand, it provides a system for improving the beam pointing accuracy of space laser communication. The system includes: a laser, an electro-optic modulator, an optical phased array, a beam splitter, an infrared camera, a signal source, and a computer. The laser is connected to the electro-optic modulator for emitting laser light. The input terminals of the electro-optic modulator are connected to both the signal source and the laser, and the output terminal of the electro-optic modulator is connected to the input terminal of the optical phased array. The electro-optic modulator is used to modulate the received laser light. The signal source is used to drive the electro-optic modulator based on the control of the computer. The input terminal of the optical phased array is connected to the output terminal of the computer. The output end of the optical phased array is connected to the incident end of the beam splitter. The optical phased array performs coarse beam pointing based on the control of the computer. The optical phased array emits laser light into space, and the laser light is emitted to the incident end of the beam splitter. The beam splitter receives a portion of the laser light and transmits the remaining portion as feedback light to the infrared camera. The input end of the infrared camera is connected to the reflecting end of the beam splitter, and the output end of the infrared camera is connected to a computer for transmitting the acquired feedback light image to the computer. The computer calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser to compensate for pointing errors.

[0006] Optionally, the laser emitted by the laser is connected to the optical signal input terminal of the electro-optic modulator using a polarization-maintaining fiber.

[0007] Optionally, the signal source is also used to transmit communication data to the electro-optic modulator based on the control of the computer.

[0008] Optionally, the communication data transmitted by the signal source is connected to the electrical signal input of the electro-optic modulator via an SMA wire.

[0009] Optionally, one side of the beam splitter is coated with an anti-reflection film. The laser emitted by the optical phased array reaches the coated surface of the beam splitter. The beam splitter emits a portion of the transmitted light as laser light and transmits a portion of the reflected light as feedback light to the infrared camera.

[0010] Optionally, the computer calculates the spot miss distance based on the received feedback light image and calculates the beam pointing angle based on the calculation result.

[0011] Optionally, the computer calculates the pointing error by comparing the calculated beam pointing angle with the beam pointing angle driving the optical phased array, and controls the laser frequency of the laser based on the pointing error to compensate for the pointing error.

[0012] Optionally, the laser is a frequency-tunable laser.

[0013] On the other hand, the present invention also provides a method for improving the beam pointing accuracy of space laser communication. The method includes: emitting laser light from a laser to an electro-optic modulator; the electro-optic modulator modulating the received laser light; a signal source driving the electro-optic modulator under computer control to load communication data onto the laser light emitted by the laser; an optical phased array coarsely pointing the laser beam angle under computer control; the optical phased array emitting the laser light into space, the laser light being emitted to the incident end of a beam splitter; the beam splitter transmitting a portion of the received laser light as laser light and a portion as feedback light to an infrared camera; the infrared camera transmitting the acquired feedback light image to the computer; the computer calculating the received feedback light image, resolving the beam pointing angle based on the calculation result, and controlling the laser frequency of the laser to compensate for pointing errors.

[0014] Optionally, the computer performs calculations on the received feedback light image, calculates the beam pointing angle based on the calculation results, and controls the laser frequency of the laser. Compensating for pointing error includes: the computer calculates the spot miss distance based on the received feedback light image, calculates the beam pointing angle based on the calculation results; calculates the pointing error based on comparing the calculated beam pointing angle with the beam pointing angle driving the optical phased array, and controls the laser frequency of the laser based on the pointing error to compensate for the pointing error.

[0015] In another aspect, the present invention also provides a computer-readable storage medium storing one or more instructions for causing a computer to perform the above-described method for improving beam pointing accuracy in space laser communication.

[0016] In another aspect, the present invention provides an electronic device, comprising: a memory and a processor; the memory storing at least one program instruction; the processor loading and executing the at least one program instruction to implement the above-described method for improving beam pointing accuracy in space laser communication.

[0017] The beneficial effects of this invention are as follows: This invention provides a system for improving the beam pointing accuracy of space laser communication. The system includes: a laser, an electro-optic modulator, an optical phased array, a beam splitter, an infrared camera, a signal source, and a computer. The laser is connected to the electro-optic modulator for emitting laser light. The input terminals of the electro-optic modulator are connected to the signal source and the laser, respectively, and the output terminal of the electro-optic modulator is connected to the input terminal of the optical phased array. The electro-optic modulator is used to modulate the received laser light. The signal source is used to drive the electro-optic modulator based on the control of the computer. The input terminal of the optical phased array is connected to the output terminal of the computer. The output end is connected to the incident end of the beam splitter. The optical phased array performs coarse beam pointing based on the control of the computer. The optical phased array emits laser light into space, which is emitted to the incident end of the beam splitter. The beam splitter receives a portion of the laser light and transmits the remaining portion as feedback light to the infrared camera. The input end of the infrared camera is connected to the reflecting end of the beam splitter, and the output end of the infrared camera is connected to a calculator to transmit the acquired feedback light image to the computer. The computer calculates the received feedback light image, determines the beam pointing angle based on the calculation results, and controls the laser frequency of the laser to compensate for pointing errors. This improves the beam pointing accuracy of long-distance space laser communication, dynamically feeds back the beam pointing angle, and compensates for pointing errors caused by environmental factors in real time. It solves the key problem of applying optical phased array antennas to space laser communication systems and provides a foundation for the miniaturization of spaceborne laser communication terminals. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a system structure diagram of an embodiment of the present invention for improving the beam pointing accuracy of space laser communication.

[0020] Figure 2 This is a flowchart of a method for improving the beam pointing accuracy of space laser communication provided in an embodiment of the present invention.

[0021] Figure 3 This is a partial block diagram of the electronic device provided in the embodiments of the present invention.

[0022] The attached figures are labeled as follows:

[0023] Laser-1;

[0024] Electro-optic modulator-2;

[0025] Optical Phased Array-3;

[0026] Beam splitter-4;

[0027] Infrared camera-5;

[0028] Signal source -6;

[0029] Computer-7. Detailed Implementation

[0030] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the figures. The process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0031] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] The present invention will now be described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0033] Example 1

[0034] Please see Figure 1 The present invention provides a system for improving beam pointing accuracy in space laser communication. The system includes: a laser 1, an electro-optic modulator 2, an optical phased array 3, a beam splitter 4, an infrared camera 5, a signal source 6, and a computer 7.

[0035] For ease of subsequent understanding, the overall inventive concept of this invention is described here:

[0036] The frequency-tunable laser is fed into an electro-optic modulator after passing through a polarization-maintaining fiber. A computer-driven signal source modulates the laser to load communication data, which is then coupled into an optical phased array antenna. The optical phased array is controlled by the computer to emit the laser beam into space. The light in space is split by a beam splitter. The beam splitter emits a portion of the light as a communication beam, while the other portion is reflected as a feedback signal to an infrared camera. The infrared camera demodulates the position of the feedback light signal, and the computer determines the beam pointing angle, then controls the frequency-tunable laser to precisely control the beam pointing.

[0037] The specific implementation method is as follows:

[0038] As an example, the laser 1 is connected to the electro-optic modulator 2 for emitting laser light. The input terminals of the electro-optic modulator 2 are connected to the signal source 6 and the laser 1, respectively, and the output terminal of the electro-optic modulator 2 is connected to the input terminal of the optical phased array 3. The electro-optic modulator 2 is used to modulate the received laser light. Specifically, the laser 1 is a frequency-tunable laser with a frequency tuning accuracy of 1 GHz; the electro-optic modulator 2 is a point light modulator 2 with a working wavelength of 1550 nm, a polarization-maintaining fiber pigtail, and a bandwidth of 10 GHz. It should be noted that the selection of the laser 1 and the electro-optic modulator 2 is not limited here, and relevant technicians can modify the components with different configurations based on actual needs.

[0039] Optionally, the laser emitted by the laser 1 is connected to the optical signal input terminal of the electro-optic modulator 2 using a polarization-maintaining fiber.

[0040] As an example, the signal source 6 is used to drive the electro-optic modulator 2 based on the control of the computer 7.

[0041] Optionally, the communication data transmitted by the signal source 6 is connected to the electrical signal input of the electro-optic modulator 2 via an SMA wire, and the computer 7 controls the signal source 6 to drive the electro-optic modulator 2 to load the communication data onto the laser emitted by the frequency-tunable laser 1.

[0042] Optionally, the signal source 6 is also used to transmit communication data to the electro-optic modulator 2 based on the control of the computer 7.

[0043] As an example, the input end of the optical phased array 3 is connected to the output end of the computer 7, and the output end of the optical phased array 3 is connected to the incident end of the beam splitter 4. The optical phased array 3 performs coarse pointing of the beam angle based on the control of the computer 7.

[0044] Optionally, the output of the electro-optic modulator 2 is connected to the optical signal input of the optical phased array 3, and the computer 7 controls the optical phased array 3 to achieve coarse beam pointing. The optical phased array 3 operates at a wavelength of 1550 nm and has 512 controlled electrodes.

[0045] As an example, the optical phased array 3 emits a laser into space, the laser is emitted to the incident end of the beam splitter 4, and the beam splitter 4 transmits part of the received laser as laser emission and part as feedback light to the infrared camera 5.

[0046] Optionally, the optical phased array 3, under the control of the computer 7, performs coarse pointing of the received light beam, i.e., large-angle pointing of the beam. This initial pointing is to control the angle of the beam. The light beam emitted into space reaches the coated surface of the beam splitter 4. The beam splitter 4 transmits 99% of the light as laser emission and reflects 1% as feedback light, which is then transmitted to the infrared camera 5. That is, one side of the beam splitter 4 is coated with an anti-reflection film. When the laser emitted by the optical phased array 3 reaches the coated surface of the beam splitter 4, the beam splitter 4 transmits a portion of the transmitted light as laser emission and a portion of the reflected light as feedback light, which is then transmitted to the infrared camera 5. Specifically, one side of the beam splitter is coated with an anti-reflection film with 99% transmittance and 1% reflectance.

[0047] As an example, the input end of the infrared camera 5 is connected to the reflective end of the beam splitter 4, and the output end of the infrared camera 5 is connected to the computer 7, for transmitting the acquired feedback light image to the computer 7.

[0048] Optionally, the infrared camera 5 transmits the collected feedback light image to the computer 7, and the computer 7 calculates the spot miss distance and beam pointing angle based on the image.

[0049] As an example, the computer 7 calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser 1 to compensate for the pointing error.

[0050] Optionally, the computer 7 calculates the pointing error by comparing the calculated beam pointing angle with the beam pointing angle driving the optical phased array 3, and controls the laser frequency of the laser 1 based on the pointing error to compensate for the pointing error. That is, the computer 7 calculates the pointing error by comparing the calculated beam pointing angle with the beam pointing angle driving the optical phased array 3, and controls the laser frequency of the frequency-tunable laser 1 to compensate for the pointing error. Through these steps, the pointing accuracy of the optical phased array can be better than 1.5 μrad, ensuring beam pointing accuracy even under environmental interference.

[0051] As can be seen from the above embodiments of this application, the technical solution described in this application improves the beam pointing accuracy of long-distance space laser communication, dynamically feeds back the beam pointing angle, and compensates for the pointing error caused by environmental factors in the open-loop pointing in real time. It solves the key problem of applying optical phased array antennas to space laser communication systems and provides a foundation for the miniaturization of spaceborne laser communication terminals.

[0052] Example 2

[0053] Please see Figure 2 This embodiment provides a method for improving the beam pointing accuracy of space laser communication, the method comprising:

[0054] S210: Laser is emitted from laser 1 to electro-optic modulator 2.

[0055] S220: The electro-optic modulator 2 modulates the received laser light.

[0056] S230: The signal source 6 drives the electro-optic modulator 2 under the control of the computer 7 to load communication data onto the laser emitted by the laser 1.

[0057] S240: The optical phased array 3, under the control of the computer 7, performs coarse beam angle pointing on the laser.

[0058] S250: The optical phased array 3 emits a laser into space. The laser is emitted to the incident end of the beam splitter 4. The beam splitter 4 transmits part of the received laser as laser emission and part as feedback light to the infrared camera 5.

[0059] S260: The infrared camera 5 transmits the acquired feedback light image to the computer 7.

[0060] S270: The computer 7 calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser 1 to compensate for the pointing error.

[0061] Optionally, the computer 7 calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser 1. The compensation for pointing error includes: the computer 7 calculates the spot miss distance based on the received feedback light image, calculates the beam pointing angle based on the calculation result; calculates the pointing error based on the calculated beam pointing angle and the beam pointing angle driving the optical phased array 3, and controls the laser frequency of the laser 1 based on the pointing error to compensate for the pointing error.

[0062] Example 3

[0063] This invention also proposes a storage medium storing a method for improving the beam pointing accuracy of space laser communication. When the program for improving the beam pointing accuracy of space laser communication is executed by a processor, it implements the steps for improving the beam pointing accuracy of space laser communication as described above. Since this storage medium adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0064] Example 4

[0065] Please see Figure 3 The present invention also provides an electronic device, including: a memory and a processor; the memory stores at least one program instruction; the processor loads and executes the at least one program instruction to implement the method for improving beam pointing accuracy of space laser communication provided in Embodiment 2.

[0066] The memory 302 and processor 301 are connected via a bus, which may include any number of interconnecting buses and bridges, connecting various circuits of one or more processors 301 and memory 302 together. The bus may also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver may be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 301 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 301.

[0067] Processor 301 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory 302 can be used to store data used by processor 301 during operation.

[0068] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A system for improving beam pointing accuracy in space laser communication, characterized in that, The system includes: a laser (1), an electro-optic modulator (2), an optical phased array (3), a beam splitter (4), an infrared camera (5), a signal source (6), and a computer (7); The laser (1) is connected to the electro-optic modulator (2) and is used to emit laser light; The input terminal of the electro-optic modulator (2) is connected to the signal source (6) and the laser (1) respectively, and the output terminal of the electro-optic modulator (2) is connected to the input terminal of the optical phased array (3). The electro-optic modulator (2) is used to modulate the received laser. The signal source (6) is used to drive the electro-optic modulator (2) based on the control of the computer (7); The input end of the optical phased array (3) is connected to the output end of the computer (7), and the output end of the optical phased array (3) is connected to the incident end of the beam splitter (4). The optical phased array (3) performs coarse pointing of the beam angle based on the control of the computer (7). The optical phased array (3) emits laser light into space. The laser light is emitted to the incident end of the beam splitter (4). The beam splitter (4) transmits part of the received laser light as laser light and part of it as feedback light to the infrared camera (5). The input end of the infrared camera (5) is connected to the reflective end of the beam splitter (4), and the output end of the infrared camera (5) is connected to the calculator (7) to transmit the collected feedback light image to the computer (7). The computer (7) calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser (1) to compensate for the pointing error. One side of the beam splitter (4) is coated with an anti-reflection film. The laser emitted by the optical phased array (3) reaches the coated surface of the beam splitter (4). The beam splitter (4) emits a portion of the transmitted light as laser light and transmits a portion of the reflected light as feedback light to the infrared camera (5). The computer (7) calculates the spot miss distance based on the received feedback light image and calculates the beam pointing angle based on the calculation result; The computer (7) calculates the pointing error by comparing the calculated beam pointing angle with the beam pointing angle of the driving optical phased array (3), and controls the laser frequency of the laser (1) based on the pointing error to compensate for the pointing error.

2. The system for improving beam pointing accuracy in space laser communication according to claim 1, characterized in that, The laser emitted by the laser (1) is connected to the optical signal input terminal of the electro-optic modulator (2) using a polarization-maintaining fiber.

3. The system for improving beam pointing accuracy in space laser communication according to claim 1, characterized in that, The signal source (6) is also used to transmit communication data to the electro-optic modulator (2) based on the control of the computer (7).

4. The system for improving beam pointing accuracy in space laser communication according to claim 3, characterized in that, The communication data transmitted by the signal source (6) is connected to the electrical signal input of the electro-optic modulator (2) via an SMA wire.

5. The system for improving beam pointing accuracy in space laser communication according to claim 1, characterized in that, The laser (1) is a frequency-tunable laser.

6. A method for improving the beam pointing accuracy of space laser communication, characterized in that, The method includes: Laser is emitted from laser (1) to electro-optic modulator (2); The electro-optic modulator (2) modulates the received laser light; The signal source (6) drives the electro-optic modulator (2) based on the control of the computer (7) to load communication data onto the laser emitted by the laser (1); The optical phased array (3) performs coarse beam pointing of the laser beam angle based on the control of the computer (7); The optical phased array (3) emits laser light into space. The laser light is emitted to the incident end of the beam splitter (4). One side of the beam splitter (4) is coated with an anti-reflection film. The beam splitter (4) transmits part of the received laser light as laser light and part of it as feedback light to the infrared camera (5). The infrared camera (5) transmits the collected feedback light image to the computer (7); The computer (7) calculates the received feedback light image, calculates the beam pointing angle based on the calculation result, and controls the laser frequency of the laser (1) to compensate for the pointing error. The computer (7) calculates the received feedback light image, determines the beam pointing angle based on the calculation results, and controls the laser frequency of the laser (1). Compensation for pointing errors includes: The computer (7) calculates the spot miss distance based on the received feedback light image and calculates the beam pointing angle based on the calculation results; The pointing error is calculated based on the beam pointing angle calculated by comparison and the beam pointing angle of the driving optical phased array (3). The laser frequency of the laser (1) is controlled based on the pointing error to compensate for the pointing error.

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